help building a housing for this pump/compressor system 1

[Space213]

hi guys, so I need some help as an entry level Mechanical engineer. I dont have much if any exp. at all in actually building something in life aside from your basic ikea tables and what not. So here at my job I have been designing a housing for this system similar to the housing you see over compressor/pump systems (basic big square sheet metal housing) I have provided the link to the solid works image below.

I have a series of questions and one of them is installing an air gauge. The OD of the air gauge is 0.8075 in and I need to make a cut out into the thin sheet metal so the air gauges can fit. If the OD is 0.8075 exactly how big should I make the Cut out? I would normally do a cut out of the same diameter but in real life how would that work I am not sure. I have never designed something where I know we would build off it so I dont want to make too many mistakes for my boss.

thanks for any advice

 

[SBaugh]

You need to ask yourself or your manager, are we farming this out to be made or do we build all our sheet metal in-house? If you are farming it out, what are their tolerances on cutting and bending? If you are keeping in-house, what are your tolerances? Make it theoretically perfect and allow for the min\max tolerances of what could happen. Then make sure that no matter which way or even both Min and Max occurs that your cutout clears the gauge. What I mean by both is you could have a bend that -1º but the cut out is @ max tolerance or it could be opposite.

Good luck,

Scott Baugh, CSWP
CAD Systems Manager
Evapar

http://www.evapar.com

"If it's not broke, Don't fix it!"

faq731-376

 

[Jboggs]

I assume you are designing a sheet metal cover to go over the mechanism we see in your attachment. First, what is the purpose of the cover? Is it to keep something (dirt, etc.) out? Second, why the "air gauge"? Is it a pressure gauge? Will the cover be pressurized? If so, what is the pressure range? If this a pressurized enclosure, then sheet metal will not do. Third, how is the gauge intended to be mounted? Is it a "bulkhead mount"? (Google "bulkhead mount".) If so, somewhere the literature will tell you the recommended hole size and mounting method. Fourth, are you sure about the number, .8075? That seems like a strange number. Are you sure its not 0.875 (7/8")?

 

[Space213]

Jboggs,

the reason for the housing is to the cover the internal layout of the system basically and to make it look more appealing. The Air Gauge and water gauge are used to measure the pressure of the flow of each through the pvc pipe and the air tubing. The gauges will be flush mounted into the housing.

The Diameter of the gauge is actually 2.43" and the Hole size I am going for is 2.48" to give a tolerance of 0.05. Is that reasonable?

The housing portion will be done by somebody more experienced so I am just trying to get a deeper idea of what I'm doing.

 

[Jboggs]

I'm confused.

1> What happened to .8075? Where did that number go?
2> Now we have two gauges, air and water. Are they the same size?
3> Are the gauges designed for "panel mounting"? If not, find some that are. Lots of them are out there. (Check Mcmaster.com.) Their literature will include all the mounting information you need.
4> In answer to your question about hole size, I would go with 2.5" (or whatever size the gauge literature recommends). The fabricator will already have the tooling for a standard size hole like that.

 

[Space213]

1. The .8075 was a smaller gauge that I chose by accident. I measured the correct gauge in our shop and it came out to be 2.43" so I sketched a hole in solidworks at 2.48" but 2.5 is good as long as there wont be any loose fit to the gauges because they are meant to be flush mounted into the housing. The gauges I got form Mcmaster where the mounts are in the back center.

Where do you get the gauge literature? sorry I am newly hired engineer (my first job) So a lot of my questions are very dumb right now.

 

[Jboggs]

No worries. We've all been there. So, you're using gauges from your own stock. Most standard gauges are meant to be mounted on their air connection. They stand alone and have no provision for panel mounting. However, some gauges are built with the intention to mount them to a panel. They have some kind of bracket or other provision to attach them to a panel. If the gauges in your stock don't have that feature they are not intended for panel mounting.

Search for pressure gauges on Mcmaster.com. Look at the options on the left. You'll see connection types and mounting types. Work your way down to click on any one part number. Click on Product Detail. You'll be shown a screen with all the information for that particular gauge, probably including a drawing and the recommended panel hole size.

I would recommend you wander around the engineering and maintenance offices and ask a few of the old farts if they know where you could find one of the old yellow McMaster-Carr catalogs. Those things were huge and worth their weight in gold for the information a budding young engineer could learn simply by thumbing through the old worn out and greasy pages. An education in itself. Highly recommended.

 

[Space213]

oh! I forgot to mention that the gauges have this type of mounting piece to them where it goes on the back ..sort of a weird piece piece that allows the gauge to have a "flush mount" to a face plate for example.

I will look into the old yellow catalogs. See I work at a start up and things are very fresh here we are still building from the ground up sort of.
Thank you for your time though

This may not be the right thread for it but do you know how you would go about mounting hardware like pumps and compressors to the inside of a unit? I know its just a matter of getting bolts/screws and nuts but exactly how to find the right size ? how would an engineer go about doing that? I will probably make a new thread on here and describe it specifically. My boss says I need to get the bolts and stuff to mount the hardware.

My plan was to just basically measure the hole size of each piece and look on mcmaster for the right screw ? If there is a much more efficient way id really really appreciate the guidance on that.

 

[Jboggs]

1> Yes, this is the wrong forum. Try Mechanical Engineering - Other Topics
2> Are you just mounting components on a structure that is already designed? Or are you supposed to design the support structure? Or are you supposed to physically mount the components yourself?
3> No, its not "just a matter of getting bolts/screws and nuts". The mounting and alignment of motor-driven components such as pumps and compressors can actually be a complex endeavor, sometimes with potentially hazardous results. Unless, that is, your only job is to find some fasteners that fit and install them in a structure that someone else has already designed.
4> As far as which bolts are the right size, this is usually a good rule of thumb - the largest standard size that will fit in the hole.

 

[Space213]

2. I will be designing the support structure for the compressor. it will be mounted vertically to an angle iron structural member and the structural member will be supported by gussets at the base. The structure I have designed should work because I have had experienced engineers look over it and say that it will work. I just need to find the right bolts and screws that will lock it into position basically.

I will make a new thread in the ME - other topics by tomorrw.